Hydrophobic benefit agents (e.g., oils) can provide moisturizing and/or conditioning benefits to the skin or to hair. At present, however, it is extremely difficult to achieve high levels of deposition of these benefit agents when delivered from personal product compositions, including but not limited to personal wash liquid cleansers and personal product bar cleansers.
While this and co-pending applications are described with skin cleansing personal product language, to the extent the structured benefit agents can be used in a variety of other compositions where deposition of benefit agents is desirable (e.g., hair, deodorant), the claims are intended to be read expansively and limited only by the structuring component.
Specifically, applicants have now unexpectedly found that use of certain “structured” benefit agents (e.g., oils and other hydrophobic benefit agents) act as so-called delivery vehicles for the benefit agent(s) which they are structuring leading to multiple benefits relative to benefit agents which are delivered without the specific structuring of the invention; or to other benefit agents used in final compositions where no other structured benefit agents are used. According to the invention, preferably the benefit agent being structured and the structuring material (e.g., crystalline wax) are separate components.
By specifically selecting particular crystalline structurant or structurants (i.e., so that the crystals have specifically defined aspect ratios), and by separately preparing structured benefit agent as a premix in the manner described (i.e., separate preparation and incorporation into product in a molten, semi-molten, or solid state), the benefit agent structurant vehicle (i.e., structured benefit agent vehicle) provides enhanced deposition as well as desired in-use and after-use sensory attributes (e.g., smooth skin feel).
As noted, such structured benefit agent also helps deposition of other benefit agents whether used in the same pre-mix (it is not clear whether they are separately structured or trapped in a network, but result is same), or whether separately added with other composition components.
Specifically, the invention relates to the use of hydrophobic benefit agent or agents structured by crystalline structurant or structurants selected from the group consisting of natural and synthetic crystalline structuring materials (e.g., waxes) wherein, when the structured benefit vehicle is separately prepared before combining with the personal product bar composition, the final composition is provided with benefit agent deposition to substrate of at least 5% greater, preferably at least 10% greater and often far more than the level of deposition obtained if the benefit agent were added without being structured or without being in the presence of a structured benefit agent in the final formulation. In one embodiment, the benefit agent is oil and structured benefit agent provides deposition greater than about 5:g/cm2 (measured in accordance with the protocol detailed in the examples). Unlike prior art references where deposition is dependent on the large size of the benefit agent droplets (e.g., >50 micrometers average droplet diameter), the deposition results of the subject invention have no requirement of large droplet size and are not dependent on size. The structured benefit agents also provide enhanced deposition of hydrophobic or hydrophilic benefit agents separately added.
Among the natural crystalline waxes which may be used as benefit agent(s) structurant are included petroleum derived waxes such as paraffins and microcrystalline waxes; as well as animal and plant (vegetable) waxes. Among the synthetic crystalline waxes which may be used are crystalline polymers such as polyethylene.
Some prior art references purport to use rheological parameters to select oils or oil blends to be used for improving deposition or providing favorable sensory feel.
U.S. Pat. No. 5,674,511 to Kacher et al., for example, describes the use of solubility parameters and four rheological parameters to select benefit agents (i.e., oil or oil blends) that can be used in moisturizing cleansing formulations to improve deposition and provide favorable sensory feels. Petrolatum and petrolatum-containing mixtures are said to be favorable selections. The reference fails to teach or suggest the building of a deformable network of crystals within the benefit agent, and which crystals must have a specific aspect ratio. The Kacher reference fails to teach or suggest that the structured benefit agent can be combined with other components in the compositions in a molten or semi-molten or solid state.
Also, it does not describe separate benefit agent and structurant, as is preferred by the subject invention (i.e., in the subject invention, if petrolatum is used, it is preferably used as a structurant to structure other benefit agents rather than itself comprise the structured benefit agent). In short, the benefit agents (e.g., oils) of Kacher clearly do not appear to be internally structured delivery vehicles like those used in the compositions of the invention which are separately prepared and wherein structurant has a defined aspect ratio.
A number of prior art references disclose generally the concept of an oil additive which can thicken or stabilize oils. They do not, however teach or disclose that specific crystalline structurant (i.e., having a defined aspect ratio), when prepared in a combination with a hydrophobic benefit agent as a premix/delivery vehicle (added in molten, semi-molten or solid state and combined with a carrying composition) will enhance deposition (by an amount of at least 5%) and/or will provide enhanced sensory benefits. Moreover, in contrast to these references where deposition is disclosed as a function of large droplet size of the benefit agent, in the subject invention deposition will occur independent of such large droplet size requirement.
U.S. Pat. No. 5,804,540 to Tsaur et al. and U.S. Pat. No. 5,661,189 to Grieveson, for example, disclose use of both crystalline or micro-crystalline waxes and hydrophobic polymers to thicken low viscosity oil so as to control the oil droplet size (i.e., it must attain a certain minimum size to deposit) as well as to maintain high lather when incorporated into a liquid cleansing composition.
U.S. Pat. No. 5,817,609 to He et al. discloses the use of hydrophobic polymers and micro-crystalline waxes to thicken low viscosity oil in bar compositions so as to achieve a large oil droplet size for deposition onto skin and to resist phase separation during bar processing.
As noted above, however, there is no discussion of the criticality of crystalline structure (aspect ratio) or that a thickened benefit agent must be separately prepared and added to the carrying composition in a molten, semi-molten or solid state. Indeed, the thickened oil is heated to 95° C. and then all of the other ingredients of the formulation are introduced into the mixer and mixed over 1-2 hours to achieve homogeneity. Further, as noted, there is no recognition that it is critical the thickener must be a natural or synthetic crystalline structuring material (as is the case with subject invention) or that deposition occurs without the need for large droplet size. Indeed, the preferred thickening materials claimed in these patents provide little to no enhancement of deposition of low viscosity oils when they are incorporated into our invention, as illustrated in the Examples Section.
In co-pending U.S. patent application Ser. No. 09/859,862 to Aronson et al. (entitled “Wet-Skin Treatment Composition”), filed May 17, 2001 and Ser. No. 09/859,849 to Aronson et al. (entitled “Method of Enhanced Moisture or Reduced Drying Using Wet-Skin Treatment Compositions”), there is disclosed benefit agents which provide a draggy feel. There is no teaching or disclosure however, of using benefit agent structurant with crystalline materials of specific aspect ratio or of how to produce such.
No prior art of which applicants are aware demonstrates the use of natural or synthetic crystalline structurants (e.g., wax) having specific aspect ratio of crystals and prepared as a premix to enhance the deposition of benefit agents (e.g., skin nutrients such as, for example, sunflower seed oil).